Artificial muscles, artificial muscle assemblies, and methods of using same

ABSTRACT

An artificial muscle including a housing, an electrode pair positioned in an electrode region of the housing, the electrode pair including a first electrode and a second electrode, the first electrode and the second electrode each including a pair of tab portions and a bridge portion, the pair of tab portions extending parallel to one another to define a gap portion between the pair of tab portions, the gap portion having a constant gap width extending along a tab length of the pair of tab portions, the bridge portion interconnecting the pair of tab portions, and a dielectric fluid housed within the housing, wherein the electrode pair is actuatable between a non-actuated state and an actuated state such that actuation from the non-actuated state to the actuated state directs the dielectric fluid into an expandable fluid region of the housing.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of co-pending U.S. ProvisionalPatent Application No. 63/338,670, filed May 5, 2022, for “Ultra-HighPerformance Artificial Muscles, Artificial Muscle Assemblies, AndMethods Of Using Same,” which is hereby incorporated by reference in itsentirety including the drawings.

TECHNICAL FIELD

The present specification generally relates to apparatus and methods forfocused inflation on at least one surface of a device, and, morespecifically, apparatus and methods for utilizing an electrode pair todirect a fluid to inflate the device.

BACKGROUND

Current robotic technologies rely on rigid components, such asservomotors to perform tasks, often in a structured environment. Thisrigidity presents limitations in many robotic applications, caused, atleast in part, by the weight-to-power ratio of servomotors and otherrigid robotics devices. The field of soft robotics improves on theselimitations by using artificial muscles and other soft actuators.Artificial muscles attempt to mimic the versatility, performance, andreliability of a biological muscle. Some artificial muscles rely onfluidic actuators, but fluidic actuators require a supply of pressurizedgas or liquid, and fluid transport must occur through systems ofchannels and tubes, limiting the speed and efficiency of the artificialmuscles. Other artificial muscles use thermally activated polymerfibers, but these are difficult to control and operate at lowefficiencies.

Accordingly, a need exists for improved artificial muscles withincreased actuator power per unit volume.

SUMMARY

In one embodiment, an artificial muscle includes: a housing including anelectrode region and an expandable fluid region; an electrode pairpositioned in the electrode region of the housing, the electrode pairincluding a first electrode and a second electrode, the first electrodeand the second electrode each including a pair of tab portions and abridge portion interconnecting the pair of tab portions, the pair of tabportions extending parallel to one another to define a gap portionbetween the pair of tab portions, the gap portion having a constant gapwidth extending along a tab length of the pair of tab portions; and adielectric fluid housed within the housing, wherein the electrode pairis actuatable between a non-actuated state and an actuated state suchthat actuation from the non-actuated state to the actuated state directsthe dielectric fluid into the expandable fluid region.

In another embodiment, an artificial muscle includes: a housingincluding an electrode region and an expandable fluid region; and anelectrode pair positioned in the electrode region of the housing, theelectrode pair including a first electrode and a second electrode, thefirst electrode and the second electrode each include a pair of tabportions and a bridge portion interconnecting the pair of tab portions,the pair of tab portions extending parallel to one another to define agap portion between the pair of tab portions, the gap portion having aconstant gap width extending along a tab length of the pair of tabportions.

In yet another embodiment, a method for actuating an artificial muscleassembly includes: generating a voltage using a power supplyelectrically coupled to an electrode pair of an artificial muscle, theartificial muscle including a housing with an electrode region and anexpandable fluid region, wherein: the electrode pair is positioned inthe electrode region of the housing; the electrode pair including afirst electrode and a second electrode, the first electrode and thesecond electrode each comprise a pair of tab portions and a bridgeportion interconnecting the pair of tab portions, the pair of tabportions extending parallel to one another to define a gap portionbetween the pair of tab portions, the gap portion having a constant gapwidth extending along a tab length of the pair of tab portions; and adielectric fluid is housed within the housing; and applying the voltageto the electrode pair of the artificial muscle, thereby actuating theelectrode pair from a non-actuated state and an actuated state such thatthe dielectric fluid is directed into the expandable fluid region of thehousing and expands the expandable fluid region.

These and additional features provided by the embodiments describedherein will be more fully understood in view of the following detaileddescription, in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative and exemplaryin nature and not intended to limit the subject matter defined by theclaims. The following detailed description of the illustrativeembodiments can be understood when read in conjunction with thefollowing drawings, where like structure is indicated with likereference numerals and in which:

FIG. 1 schematically depicts an exploded view of an artificial muscle,according to one or more embodiments shown and described herein;

FIG. 2 schematically depicts a top view of the artificial muscle of FIG.1 , according to one or more embodiments shown and described herein;

FIG. 3 schematically depicts an exploded, cross-sectional view of theartificial muscle of FIG. 1 taken along line 3-3 in FIG. 2 , accordingto one or more embodiments shown and described herein;

FIG. 4 schematically depicts an assembled, cross-sectional view of theartificial muscle of FIG. 1 taken along line 3-3 in FIG. 2 in anon-actuated state, according to one or more embodiments shown anddescribed herein;

FIG. 5 schematically depicts an assembled, cross-sectional view of theartificial muscle of FIG. 1 taken along line 3-3 in FIG. 2 in anactuated state, according to one or more embodiments shown and describedherein;

FIG. 6 depicts a top view of the artificial muscle of FIG. 1 , accordingto one or more embodiments shown and described herein; and

FIG. 7 schematically depicts an actuation system for operating theartificial muscle of FIG. 1 , according to one or more embodiments shownand described herein.

DETAILED DESCRIPTION

Embodiments described herein are directed to artificial muscles andartificial muscle assemblies that include a plurality of artificialmuscles. The artificial muscles described herein are actuatable toselectively raise and lower a region of the artificial muscles toprovide a selective, on demand inflated expandable fluid region. Theartificial muscles include a housing and an electrode pair. A dielectricfluid is housed within the housing, and the housing includes anelectrode region and an expandable fluid region, where the electrodepair is positioned in the electrode region. The electrode pair includesa first electrode and a second electrode. The electrode pair isactuatable between a non-actuated state and an actuated state such thatactuation from the non-actuated state to the actuated state directs thedielectric fluid into the expandable fluid region. This expands theexpandable fluid region, raising a portion of the artificial muscle ondemand. Further, the first electrode and the second electrode eachincludes a pair of tab portions and a bridge portion interconnecting thetab portions. The tab portion and bridge portion design of the electrodepair facilitates a zippering actuation motion to increase the force perunit volume achievable by actuation of the artificial muscle. Variousembodiments of the artificial muscle and the operation of the artificialmuscle are described in more detail herein. Whenever possible, the samereference numerals will be used throughout the drawings to refer to thesame or like parts.

Referring now to FIG. 1 , an artificial muscle 100 is shown. Theartificial muscle 100 includes a housing 102, an electrode pair 104,including a first electrode 106 and a second electrode 108, coupled orotherwise fixed to opposite surfaces of the housing 102, a firstelectrical insulator layer 110 fixed to the first electrode 106, and asecond electrical insulator layer 112 fixed to the second electrode 108.In some embodiments, the housing 102 is a one-piece monolithic layerincluding a pair of opposite inner surfaces, such as a first innersurface 114 and a second inner surface 116, and a pair of opposite outersurfaces, such as a first outer surface 118 and a second outer surface120. In some embodiments, the first inner surface 114 and the secondinner surface 116 of the housing 102 are heat sealable. In embodiments,the housing 102 may be a pair of individually fabricated film layers,such as a first film layer 122 and a second film layer 124. Thus, thefirst film layer 122 includes the first inner surface 114 and the firstouter surface 118, and the second film layer 124 includes the secondinner surface 116 and the second outer surface 120.

Throughout the ensuing description, reference may be made to the housing102 including the first film layer 122 and the second film layer 124, asopposed to the one-piece housing. It should be understood that eitherarrangement is contemplated. In some embodiments, the first film layer122 and the second film layer 124 generally include the same structureand composition. For example, in some embodiments, the first film layer122 and the second film layer 124 each comprises biaxially orientedpolypropylene (BOPP).

The first electrode 106 and the second electrode 108 are each positionedbetween the first film layer 122 and the second film layer 124. In someembodiments, the first electrode 106 and the second electrode 108 areeach aluminum-coated polyester such as, for example, Mylar®. In someembodiments, the first electrode 106 and the second electrode 108 may beflexible. In addition, one of the first electrode 106 and the secondelectrode 108 is a negatively charged electrode and the other of thefirst electrode 106 and the second electrode 108 is a positively chargedelectrode. For purposes discussed herein, either electrode 106, 108 maybe positively charged so long as the other electrode 106, 108 of theartificial muscle 100 is negatively charged.

Referring still to FIG. 1 , the first electrode 106 has a film-facingsurface 126 and an opposite inner surface 128. The first electrode 106is positioned against the first film layer 122, specifically, the firstinner surface 114 of the first film layer 122. In addition, the firstelectrode 106 includes a first terminal 130 extending from the firstelectrode 106 past an edge of the first film layer 122 such that thefirst terminal 130 can be connected to a power supply to actuate thefirst electrode 106. Specifically, the first terminal 130 is coupled,either directly or in series, to a power supply and a controller of anactuation system 200, as shown in FIG. 7 . Similarly, the secondelectrode 108 has a film-facing surface 148 and an opposite innersurface 150. The second electrode 108 is positioned against the secondfilm layer 124, specifically, the second inner surface 116 of the secondfilm layer 124. The second electrode 108 includes a second terminal 152extending from the second electrode 108 past an edge of the second filmlayer 124 such that the second terminal 152 can be connected to a powersupply and a controller of the actuation system 200 to actuate thesecond electrode 108.

In embodiments, the first electrode 106 includes a pair of tab portions132 and a bridge portion 140. The bridge portion 140 is positionedbetween the tab portions 132 and interconnects the tab portions 132.Although only a pair of tab portions 132 are illustrated extendingparallel to one another with a single bridge portion 140 extendingtherebetween, it should be appreciated that the first electrode 106 mayinclude more than two tab portions 132 and more than one bridge portion140. For example, the first electrode 106 may include three tab portions132 and a pair of bridge portions 140 with each bridge portion 140extending between a pair of adjacent tab portions 132. Each tab portion132 has a first end 134 and an opposite second end 136 proximate thefirst terminal 130 of the first electrode 106 and defining a portion ofan outer perimeter 138 of the first electrode 106. As shown in FIG. 2 ,the first terminal 130 extends from the second end 136 of one of the tabportions 132 and is integrally formed therewith. Each bridge portion 140has a first end 142 and an opposite second end 144 defining anotherportion of the outer perimeter 138 of the first electrode 106.

Like the first electrode 106, in embodiments, the second electrode 108includes a pair of tab portions 154 and a bridge portion 162. The bridgeportion 162 is positioned between the tab portions 154 and interconnectsthe tab portions 154. Although only a pair of tab portions 154 areillustrated extending parallel to one another with a single bridgeportion 162 extending therebetween, it should be appreciated that thesecond electrode 108 may include more than two tab portions 154 and morethan one bridge portion 162. For example, the second electrode 108 mayinclude three tab portions 154 and a pair of bridge portions 162 witheach bridge portion 162 extending between a pair of adjacent tabportions 154. Each tab portion 154 has a first end 156 and an oppositesecond end 158 proximate the second terminal 152 of the second electrode108 and defining a portion of an outer perimeter 160 of the secondelectrode 108. As shown in FIG. 1 , the second terminal 152 extends fromthe second end 158 of one of the tab portions 154 and is integrallyformed therewith. Each bridge portion 162 has a first end 164 and anopposite second end 166 defining another portion of the outer perimeter160 of the second electrode 108.

Referring still to FIG. 1 , the first electrical insulator layer 110 andthe second electrical insulator layer 112 have a geometry generallycorresponding to the first electrode 106 and the second electrode 108,respectively. Thus, the first electrical insulator layer 110 and thesecond electrical insulator layer 112 each have tab portions 170, 172,and bridge portions 174, 176 corresponding to like portions on the firstelectrode 106 and the second electrode 108. Further, the firstelectrical insulator layer 110 and the second electrical insulator layer112 each have an outer perimeter 178, 180 corresponding to the outerperimeter 138 of the first electrode 106 and the outer perimeter 160 ofthe second electrode 108, respectively, when positioned thereon.

It should be appreciated that, in some embodiments, the first electricalinsulator layer 110 and the second electrical insulator layer 112generally include the same structure and composition. As such, in someembodiments, the first electrical insulator layer 110 and the secondelectrical insulator layer 112 each includes a sealable surface 182, 184and an opposite non-sealable surface 186, 188, respectively. Thus, insome embodiments, the first electrical insulator layer 110 and thesecond electrical insulator layer 112 are each a polymer tape adhered tothe inner surface 128 of the first electrode 106 and the inner surface150 of the second electrode 108, respectively. In embodiments, the firstelectrical insulator layer 110 and the second electrical insulator layer112 each comprises poly(vinylidene fluoride)-co-hexafluoropropylene(PVDF-HFP) film. Each of the first electrical insulator layer 110 andthe second electrical insulator layer 112 may have a thickness ofbetween 1 micron and 3 microns. In embodiments, each of the firstelectrical insulator layer 110 and the second electrical insulator layer112 may have a thickness of 2 microns. The first electrical insulatorlayer 110 and the second electrical insulator layer 112 may be attachedto the first electrode 106 and the second electrode 108, respectively,by being vacuum heat sealed.

Referring now to FIG. 2 , the artificial muscle 100 is shown in itsassembled form with the first terminal 130 of the first electrode 106and the second terminal 152 of the second electrode 108 extending pastan outer perimeter of the housing 102, i.e., the first film layer 122and the second film layer 124. As shown in FIG. 2 , the second electrode108 is stacked on top of the first electrode 106 and, therefore, onlythe first terminal 130 of the first electrode 106 is shown and the firstfilm layer 122, the first electrical insulator layer 110, and the secondelectrical insulator layer 112 are not shown.

With reference to FIGS. 2-5 , in an assembled form, the first electrode106, the second electrode 108, the first electrical insulator layer 110,and the second electrical insulator layer 112 are sandwiched between thefirst film layer 122 and the second film layer 124. The first film layer122 is partially sealed to the second film layer 124 at an areasurrounding the outer perimeter 138 of the first electrode 106 and theouter perimeter 160 of the second electrode 108. In some embodiments,the first film layer 122 is heat-sealed to the second film layer 124.Specifically, in some embodiments, the first film layer 122 is sealed tothe second film layer 124 to define a sealed portion 190 at leastpartially surrounding the first electrode 106 and the second electrode108. The first film layer 122 and the second film layer 124 may besealed in any suitable manner, such as using an adhesive, heat sealing,or the like.

An unsealed portion 192 is provided adjacent the sealed portion 190 atwhich the first film layer 122 is prevented from sealing to the secondfilm layer 124. The unsealed portion 192 of the housing 102 includes anelectrode region 194, in which the electrode pair 104 is provided, andan expandable fluid region 196, which is surrounded by the electroderegion 194 and the sealed portion 190. Although not shown, the housing102 may be cut to conform to the geometry of the electrode pair 104 andreduce the size of the artificial muscle 100, namely, the size of thesealed portion 190.

As shown in FIGS. 4 and 5 , a dielectric fluid 198 is provided withinthe unsealed portion 192 and flows freely between the first electrode106 and the second electrode 108. A “dielectric” fluid as used herein isa medium or material that transmits electrical force without conductionand as such has low electrical conductivity. Some non-limiting exampledielectric fluids include perfluoroalkanes, transformer oils, anddeionized water. It should be appreciated that the dielectric fluid 198may be injected into the unsealed portion 192 of the artificial muscle100 using a needle or other suitable injection device.

Referring again to FIG. 3 , in embodiments, the first film layer 122 andthe second film layer 124 each include more than one layer. For example,the first film layer 122 includes a first inner subfilm layer 122 adefining the first inner surface 114 and a first outer subfilm layer 122b defining the first outer surface 118, and the second film layer 124includes a second inner subfilm layer 124 a defining the second innersurface 116 and a second outer subfilm layer 124 b defining the secondouter surface 120. In embodiments, one or more additional layers may beprovided between the first inner subfilm layer 122 a and the first outersubfilm layer 122 b. Similarly, in embodiments, one or more additionallayers may be provided between the second inner subfilm layer 124 a andthe second outer subfilm layer 124 b.

In embodiments, as shown in FIG. 3 , the first film layer 122 includesthe first inner subfilm layer 122 a, the first outer subfilm layer 122b, a first reinforcing layer 122 c, and a first backing layer 122 d. Thefirst reinforcing layer 122 c is provided between the first innersubfilm layer 122 a and the first backing layer 122 d. As shown, only asingle first reinforcing layer 122 c is provided. However, it should beappreciated that a plurality of first reinforcing layers 122 c may beprovided between the first inner subfilm layer 122 a and the firstbacking layer 122 d. The first reinforcing layer 122 c may be in contactwith and heat sealed between each of the first inner subfilm layer 122 aand the first backing layer 122 d. Accordingly, the first backing layer122 d is dimensioned to be greater than the first reinforcing layer 122c so that the first backing layer 122 d may be heat sealed to the firstinner subfilm layer 122 a and enclose the first reinforcing layer 122 ctherebetween. Additionally, in embodiments, the first backing layer 122d comprises the same material as the first inner subfilm layer 122 a andthe first outer subfilm layer 122 b. In embodiments, the first backinglayer 122 d partially overlaps the first electrode 106, specifically thebridge portion 140 of the first electrode 106. In embodiments, the firstbacking layer 122 d also overlaps a portion of the first electricalinsulator layer 110. The first reinforcing layer 122 c has an elasticitygreater than an elasticity of the material forming each of the firstinner subfilm layer 122 a, the first outer subfilm layer 122 b, and thefirst backing layer 122 d. In embodiments, the first reinforcing layer122 c includes a unidirectional laminate fabric material constructedfrom a sheet of ultra-high-molecular-weight polyethylene (UHMWPE)laminated between two sheets of polyester. In embodiments, the firstreinforcing layer 122 c has a thickness of greater than or equal to 1mil and less than or equal to 4 mil. In embodiments, the firstreinforcing layer 122 c has a thickness of greater than or equal to 1mil and less than or equal to 2 mil. In embodiments, the firstreinforcing layer 122 c is a fabric material such as, for example,Dyneema®, Kevlar, and the like. However, other suitable materials may beutilized for the first reinforcing layer 122 c.

Similarly, as shown in FIG. 3 , the second film layer 124 includes thesecond inner subfilm layer 124 a, the second outer subfilm layer 124 b,a second reinforcing layer 124 c, and a second backing layer 124 d. Thesecond reinforcing layer 124 c is provided between the second innersubfilm layer 124 a and the second backing layer 124 d. As shown, only asingle second reinforcing layer 124 c is provided. However, it should beappreciated that a plurality of second reinforcing layers 124 c may beprovided between the second inner subfilm layer 124 a and the secondbacking layer 124 d. The second reinforcing layer 124 c may be incontact with and heat sealed between each of the second inner subfilmlayer 124 a and the second backing layer 124 d. Accordingly, the secondbacking layer 124 d is dimensioned to be greater than the secondreinforcing layer 124 c so that the second backing layer 124 d may beheat sealed to the second inner subfilm layer 124 a and enclose thesecond reinforcing layer 124 c therebetween. Additionally, inembodiments, the second backing layer 124 d comprises the same materialas the second inner subfilm layer 124 a and the second outer subfilmlayer 124 b. In embodiments, the second backing layer 124 d partiallyoverlaps the second electrode 108, specifically the bridge portion 162of the second electrode 108. In embodiments, the second backing layer124 d also overlaps a portion of the second electrical insulator layer112. The second reinforcing layer 124 c has an elasticity greater thanan elasticity of the material forming each of the second inner subfilmlayer 124 a, the second outer subfilm layer 124 b, and the secondbacking layer 124 d. In embodiments, the second reinforcing layer 124 cincludes a unidirectional laminate fabric material constructed from asheet of UHMWPE laminated between two sheets of polyester. Inembodiments, the second reinforcing layer 124 c has a thickness ofgreater than or equal to 1 mil and less than or equal to 4 mil. Inembodiments, the second reinforcing layer 124 c has a thickness ofgreater than or equal to 1 mil and less than or equal to 2 mil. Inembodiments, the second reinforcing layer 124 c is a fabric materialsuch as, for example, Dyneema®, Kevlar, and the like. However, othersuitable materials may be utilized for the second reinforcing layer 124c.

It should be appreciated that the first backing layer 122 d and thesecond backing layer 124 d are not sealable to one another such as, forexample, by being heat sealed. As such, the expandable fluid region 196(FIG. 4 ) is provided between the first backing layer 122 d and thesecond backing layer 124 d. In addition, the film-facing surface 126 ofthe first electrode 106 is coupled or otherwise fixed to the second filmlayer 124 by any suitable methods such as, for example, heat-sealing orthe like and, similarly, the film-facing surface 148 of the secondelectrode 108 is coupled or otherwise fixed to the second film layer 124by any suitable methods such as, for example, heat-sealing or the like.

Due to the first reinforcing layer 122 c and the second reinforcinglayer 124 c having an elasticity greater than an elasticity of the otherlayers of the housing 102 permanent deformation of the housing 102 ofthe artificial muscle 100 resulting from repeated use is prevented.Specifically, the BOPP forming the housing 102 is known to permanentlydistend or deform when subjected to forces greater than 15N.Accordingly, the first reinforcing layer 122 c and the secondreinforcing layer 124 c reduce this permanent deformation.

Referring again to FIGS. 4 and 5 , the electrode pair 104 is providedwithin the electrode region 194 of the unsealed portion 192 of thehousing 102 and the artificial muscle 100 is actuatable between anon-actuated state (FIG. 4 ) and an actuated state (FIG. 5 ). It shouldbe appreciated that the first film layer 122 and the second film layer124 are generally depicted in FIGS. 4 and 5 .

As shown in FIG. 4 , in the non-actuated state, the first electrode 106and the second electrode 108 are initially partially spaced apart fromone another, at least at the first end 134, 156 of the tab portions 132,154. Due to the first film layer 122 being sealed to the second filmlayer 124 around the electrode pair 104, the second end 136, 158 of thetab portions 132, 154 are brought into contact with one another. Thus,dielectric fluid 198 is provided between the first electrode 106 and thesecond electrode 108, thereby separating the first end 134, 156 of thetab portions 132, 154 proximate the expandable fluid region 196. Statedanother way, when in the non-actuated state, a distance between thefirst end 134 of the tab portion 132 of the first electrode 106 and thefirst end 156 of the tab portion 154 of the second electrode 108 isgreater than a distance between the second end 136 of the tab portion132 of the first electrode 106 and the second end 158 of the tab portion154 of the second electrode 108. This results in the electrode pair 104zippering toward the expandable fluid region 196 when actuated. In thenon-actuated state, the expandable fluid region 196 has a first heightH1.

As shown in FIG. 5 , in the actuated state, the first electrode 106 andthe second electrode 108 are brought into contact with and orientedparallel to one another to force the dielectric fluid 198 into theexpandable fluid region 196. This causes the dielectric fluid 198 toflow from the electrode region 194 between the first electrode 106 andthe second electrode 108, and into the expandable fluid region 196 toinflate the expandable fluid region 196. Accordingly, when actuated, thefirst electrode 106 and the second electrode 108 zipper toward oneanother from the second ends 144, 158 of the tab portions 132, 154thereof, thereby pushing the dielectric fluid 198 into the expandablefluid region 196. When in the actuated state, the first electrode 106and the second electrode 108 are parallel to one another. In theactuated state, the dielectric fluid 198 flows into the expandable fluidregion 196 to inflate the expandable fluid region 196. As such, thefirst film layer 122 and the second film layer 124 expand in oppositedirections. In the actuated state, the expandable fluid region 196 has asecond height H2, which is greater than the first height H1 of theexpandable fluid region 196 when in the non-actuated state. Although notshown, it should be noted that the electrode pair 104 may be partiallyactuated to a position between the non-actuated state and the actuatedstate. This would allow for partial inflation of the expandable fluidregion 196 and adjustments when necessary.

To move the first electrode 106 and the second electrode 108 toward oneanother, a voltage is applied by a power supply. In some embodiments, avoltage of up to 10 kV may be provided from the power supply to inducean electric field through the dielectric fluid 198. The resultingattraction between the first electrode 106 and the second electrode 108pushes the dielectric fluid 198 into the expandable fluid region 196.Pressure from the dielectric fluid 198 within the expandable fluidregion 196 causes the first film layer 122 to deform in a first axialdirection and causes the second film layer 124 to deform in an oppositesecond axial direction. Once the voltage being supplied to the firstelectrode 106 and the second electrode 108 is discontinued, the firstelectrode 106 and the second electrode 108 return to their initial,non-parallel position in the non-actuated state.

It should be appreciated that the present embodiments disclosed herein,specifically, the tab portions 132, 154 with the interconnecting bridgeportions 140, 162 (FIG. 1 ), provide a number of improvements overactuators, such as HASEL actuators, that do not include the tab portions132, 154. Embodiments of the artificial muscle 100 including a pair oftab portions 132, 154 on each of the first electrode 106 and the secondelectrode 108, respectively, reduces the overall mass and thickness ofthe artificial muscle 100, reduces the amount of voltage required duringactuation, and decreases the total volume of the artificial muscle 100without reducing the amount of resulting force after actuation ascompared to known HASEL actuators. More particularly, the tab portions132, 154 of the artificial muscle 100 provide zipping fronts that resultin increased actuation power by providing localized and uniformhydraulic actuation of the artificial muscle 100 compared to known HASELactuators. The bridge portions 140, 162 (FIG. 1 ) interconnecting thetab portions 132, 154 also limit buckling of the tab portions 132, 154by maintaining the distance between adjacent tab portions 132, 154during actuation. Because the bridge portions 140, 162 are integrallyformed with the tab portions 132, 154, the bridge portions 140, 162(FIG. 1 ) also prevent leakage between the tab portions 132, 154 byeliminating attachment locations that provide an increased risk ofrupturing.

Moreover, the size of the first electrode 106 and the second electrode108 is proportional to the amount of displacement of the dielectricfluid 198. Therefore, when greater displacement within the expandablefluid region 196 is desired, the size of the electrode pair 104 isincreased relative to the size of the expandable fluid region 196.

Referring now to FIG. 6 , certain components of the artificial muscle100 are illustrated including the first electrode 106 and the firstreinforcing layer 122 c within the housing 102. However, it should beappreciated that the first electrode 106 and the second electrode 108have the same dimensions. Similarly, it should be appreciated that thefirst reinforcing layer 122 c and the second reinforcing layer 124 chave the same dimensions. Accordingly, only the dimensions of the firstelectrode 106 and the first reinforcing layer 122 c are provided herein.

With respect to the first electrode 106, each tab portion 132 of thefirst electrode 106 has a tab length Tl and the bridge portion 140 has abridge length Bl. The tab length Tl is a distance from the first end 134of the tab portion 132 to the second end 136 of the tab portion 132, andthe bridge length Bl is a distance from the first end 142 of the bridgeportion 140 to the second end 144 of the bridge portion 140.Accordingly, the tab length Tl of each tab portion 132 is longer thanthe bridge length Bl of the bridge portion 140. In addition, each tabportion 132 has a tab width Tw extending between opposite sides 127 of arespective tab portion 132. A gap portion 133 is formed between thesides 127 of adjacent tab portions 132 and adjacent the bridge portion140. The gap portion 133 has a gap width Gw extending between oppositesides 127 of adjacent tab portions 132 and a gap length Gl extendingfrom the second end 144 of the bridge portion 140 and the second end 136of the tab portions 132. The first electrode 106 has a total tab widthTTw extending across each of the pair of tab portions 132 and the gapportion 133.

In embodiments, the tab portions 132 of the first electrode 104 definecorners formed at substantially 90 degree angles. Accordingly, inembodiments, the tab portions 132 of the first electrode 108 arerectangular in shape with the first terminal 130 extending from one ofthe tab portion 132. Additionally, in embodiments, the bridge portion140 extends between the tab portions 132 to form corners partiallydefining the gap portion 133, the corners also being formed atsubstantially 90 degree angles such that the gap portion 133 isrectangular in shape between the tab portions 132. As discussed herein,the tab portions 132 extend parallel to one another and, moreparticularly, adjacent sides 127 of opposite tab portions 132 extendparallel to one another such that the gap portion 133 has a constant gapwidth Gw extending along the tab length Tl of the tab portions 132,which is also constant.

With respect to the first reinforcing layer 122 c, the first reinforcinglayer 122 c has a reinforcing layer length Rl extending in a directionparallel to the tab length Tl. The first reinforcing layer 122 c alsohas a reinforcing layer width Rw. In embodiments, the reinforcing layerwidth Rw is equal to the total tab width TTw of the first electrode 106.

In a first embodiment of the artificial muscle 100, the tab length Tl isgreater than or equal to 3 cm and less than or equal to 4 cm. The tabwidth Tw is greater than or equal to 1 cm and less than or equal to 2cm. The bridge length Bl is greater than or equal to 0.05 cm and lessthan or equal to 1 cm. The gap width Gw is greater than or equal to 0.5cm and less than or equal to 1 cm. The gap length Gl is greater than orequal to 3 cm and less than or equal to 4 cm. The total tab width TTw isgreater than or equal to 3 cm and less than or equal to 4.5 cm. Thereinforcing layer length Rl of the first reinforcing layer 122 c isgreater than or equal to 2 cm and less than or equal to 3 cm.

In another embodiment of the artificial muscle 100, the tab length Tl isgreater than or equal to 6 cm and less than or equal to 7 cm. The tabwidth Tw is greater than or equal to 2.5 cm and less than or equal to 4cm. The bridge length Bl is greater than or equal to 0.1 cm and lessthan or equal to 1 cm. The gap width Gw is greater than or equal to 1 cmand less than or equal to 2 cm. The gap length Gl is greater than orequal to 6 cm and less than or equal to 7 cm. The total tab width TTw isgreater than or equal to 7 cm and less than or equal to 8 cm. Thereinforcing layer length Rl of the first reinforcing layer 122 c isgreater than or equal to 4 cm and less than or equal to 6 cm.

In yet another embodiment of the artificial muscle 100, the tab lengthTl is greater than or equal to 12 cm and less than or equal to 13 cm.The tab width Tw is greater than or equal to 2.5 cm and less than orequal to 4 cm. The bridge length Bl is greater than or equal to 0.1 cmand less than or equal to 1 cm. The gap width Gw is greater than orequal to 1 cm and less than or equal to 2 cm. The gap length Gl isgreater than or equal to 11 cm and less than or equal to 13 cm. Thetotal tab width TTw is greater than or equal to 7 cm and less than orequal to 8 cm. The reinforcing layer length Rl of the first reinforcinglayer 122 c is greater than or equal to 4 cm and less than or equal to 6cm.

It should be appreciated that the dimensions discussed herein are notlimiting and other dimensions are contemplated as being within the scopeof the present disclosure. For example, additional bridge lengths Bl arecontemplated such as, for example, equal to or greater than 15 mm andless than or equal to 20 mm, equal to or greater than 10 mm and lessthan or equal to 15 mm, equal to or greater than 5 mm and less than orequal to 10 mm, and equal to or greater than 1 mm and less than or equalto 5 mm.

Referring now to FIG. 7 , an actuation system 200 may be provided foroperating an artificial muscle such as, for example, the artificialmuscle 100, between the non-actuated state and the actuated state. Theactuation system 200 may also be provided for operating the artificialmuscles 100 or an artificial muscle assembly including a plurality ofthe artificial muscles 100 arranged in any suitable configuration suchas, for example, in a stacked formation such that the expandable fluidregion 196 of each artificial muscle 100 is axially positioned tooverlap an adjacent expandable fluid region 196 of another artificialmuscle 100. Thus, the actuation system 200 may include a controller 202,an operating device 204, a power supply 206, and a communication path208. The various components of the actuation system 200 will now bedescribed.

The controller 202 includes a processor 210 and a non-transitoryelectronic memory 212 to which various components are communicativelycoupled. In some embodiments, the processor 210 and the non-transitoryelectronic memory 212 and/or the other components are included within asingle device. In other embodiments, the processor 210 and thenon-transitory electronic memory 212 and/or the other components may bedistributed among multiple devices that are communicatively coupled. Thecontroller 202 includes non-transitory electronic memory 212 that storesa set of machine-readable instructions. The processor 210 executes themachine-readable instructions stored in the non-transitory electronicmemory 212. The non-transitory electronic memory 212 may comprise RAM,ROM, flash memories, hard drives, or any device capable of storingmachine-readable instructions such that the machine-readableinstructions can be accessed by the processor 210. Accordingly, theactuation system 200 described herein may be implemented in anyconventional computer programming language, as pre-programmed hardwareelements, or as a combination of hardware and software components. Thenon-transitory electronic memory 212 may be implemented as one memorymodule or a plurality of memory modules.

In some embodiments, the non-transitory electronic memory 212 includesinstructions for executing the functions of the actuation system 200.The instructions may include instructions for operating the artificialmuscle 100 based on a user command.

The processor 210 may be any device capable of executingmachine-readable instructions. For example, the processor 210 may be anintegrated circuit, a microchip, a computer, or any other computingdevice. The non-transitory electronic memory 212 and the processor 210are coupled to the communication path 208 that provides signalinterconnectivity between various components and/or modules of theactuation system 200. Accordingly, the communication path 208 maycommunicatively couple any number of processors with one another, andallow the modules coupled to the communication path 208 to operate in adistributed computing environment. Specifically, each of the modules mayoperate as a node that may send and/or receive data. As used herein, theterm “communicatively coupled” means that coupled components are capableof exchanging data signals with one another such as, for example,electrical signals via conductive medium, electromagnetic signals viaair, optical signals via optical waveguides, and the like.

As schematically depicted in FIG. 7 , the communication path 208communicatively couples the processor 210 and the non-transitoryelectronic memory 212 of the controller 202 with a plurality of othercomponents of the actuation system 200. For example, the actuationsystem 200 depicted in FIG. 7 includes the processor 210 and thenon-transitory electronic memory 212 communicatively coupled with theoperating device 204 and the power supply 206.

The operating device 204 allows for a user to control operation of theartificial muscle 100. In some embodiments, the operating device 204 maybe a switch, toggle, button, or any combination of controls to provideuser operation. As a non-limiting example, a user may actuate theartificial muscle 100 into the actuated state by activating controls ofthe operating device 204 to a first position. While in the firstposition, the artificial muscle 100 will remain in the actuated state.The user may switch the artificial muscle 100 into the non-actuatedstate by operating the controls of the operating device 204 out of thefirst position and into a second position.

The operating device 204 is coupled to the communication path 208 suchthat the communication path 208 communicatively couples the operatingdevice 204 to other modules of the actuation system 200. The operatingdevice 204 may provide a user interface for receiving user instructionsas to a specific operating configuration of the artificial muscle 100.In addition, user instructions may include instructions to operate theartificial muscle 100 only at certain conditions.

The power supply 206 (e.g., battery) provides power to the artificialmuscle 100. In some embodiments, the power supply 206 is a rechargeabledirect current power source. It is to be understood that the powersupply 206 may be a single power supply or battery for providing powerto the artificial muscle 100. A power adapter (not shown) may beprovided and electrically coupled via a wiring harness or the like forproviding power to the artificial muscle 100 via the power supply 206.

In some embodiments, the actuation system 200 also includes a displaydevice 214. The display device 214 is coupled to the communication path208 such that the communication path 208 communicatively couples thedisplay device 214 to other modules of the actuation system 200. Thedisplay device 214 may output a notification in response to an actuationstate of the artificial muscle 100 or indication of a change in theactuation state of the artificial muscle 100. Moreover, the displaydevice 214 may be a touchscreen that, in addition to providing opticalinformation, detects the presence and location of a tactile input upon asurface of or adjacent to the display device 214. Accordingly, thedisplay device 214 may include the operating device 204 and receivemechanical input directly upon the optical output provided by thedisplay device 214.

In some embodiments, the actuation system 200 includes network interfacehardware 216 for communicatively coupling the actuation system 200 to aportable device 218 via a network 220. The portable device 218 mayinclude, without limitation, a smartphone, a tablet, a personal mediaplayer, or any other electric device that includes wirelesscommunication functionality. It is to be appreciated that, whenprovided, the portable device 218 may serve to provide user commands tothe controller 202, instead of the operating device 204. As such, a usermay be able to control or set a program for controlling the artificialmuscle 100 without utilizing the controls of the operating device 204.Thus, the artificial muscle 100 may be controlled remotely via theportable device 218 wirelessly communicating with the controller 202 viathe network 220.

From the above, it is to be appreciated that defined herein is anartificial muscle for inflating or deforming a surface of an object byselectively actuating the artificial muscle to raise and lower a regionthereof. This provides a low profile inflation member that may operateon demand.

It is noted that the terms “substantially” and “about” may be utilizedherein to represent the inherent degree of uncertainty that may beattributed to any quantitative comparison, value, measurement, or otherrepresentation. These terms are also utilized herein to represent thedegree by which a quantitative representation may vary from a statedreference without resulting in a change in the basic function of thesubject matter at issue.

While particular embodiments have been illustrated and described herein,it should be understood that various other changes and modifications maybe made without departing from the scope of the claimed subject matter.Moreover, although various aspects of the claimed subject matter havebeen described herein, such aspects need not be utilized in combination.It is therefore intended that the appended claims cover all such changesand modifications that are within the scope of the claimed subjectmatter.

What is claimed is:
 1. An artificial muscle comprising: a housingcomprising an electrode region and an expandable fluid region; anelectrode pair positioned in the electrode region of the housing, theelectrode pair comprising a first electrode and a second electrode, thefirst electrode and the second electrode each comprising a pair of tabportions and a bridge portion interconnecting the pair of tab portions,the pair of tab portions extending parallel to one another to define agap portion between the pair of tab portions, the gap portion having aconstant gap width extending along a tab length of the pair of tabportions; and a dielectric fluid housed within the housing, wherein theelectrode pair is actuatable between a non-actuated state and anactuated state such that actuation from the non-actuated state to theactuated state directs the dielectric fluid into the expandable fluidregion.
 2. The artificial muscle of claim 1, wherein the housingcomprises a first film layer and a second film layer partially sealed toone another to define a sealed portion of the housing, the housingfurther defining an unsealed portion surrounded by the sealed portion,wherein the electrode region and the expandable fluid region of thehousing are disposed in the unsealed portion.
 3. The artificial muscleof claim 2, wherein the first film layer and the second film layer eachcomprise one or more biaxially oriented polypropylene films.
 4. Theartificial muscle of claim 1, further comprising a first electricalinsulator layer vacuum heat sealed to an inner surface of the firstelectrode and a second electrical insulator layer vacuum heat sealed toan inner surface of the second electrode.
 5. The artificial muscle ofclaim 1, wherein the first electrode and the second electrode are eachan aluminum-coated polyester electrode.
 6. The artificial muscle ofclaim 1, wherein: when the electrode pair is in the non-actuated state,the first electrode and the second electrode are non-parallel to oneanother; and when the electrode pair is in the actuated state, the firstelectrode and the second electrode are parallel to one another, suchthat the first electrode and the second electrode are configured tozipper toward one another when actuated from the non-actuated state tothe actuated state.
 7. The artificial muscle of claim 1, wherein thepair of tab portions of each of the first electrode and the secondelectrode extend parallel to one another and define a gap portionadjacent the bridge portion of each of the first electrode and thesecond electrode.
 8. The artificial muscle of claim 1, wherein thehousing comprises a first reinforcing layer and a second reinforcinglayer positioned substantially within the expandable fluid region, thefirst reinforcing layer at least partially overlaps the bridge portionof the first electrode, and the second reinforcing layer at leastpartially overlaps the bridge portion of the second electrode.
 9. Theartificial muscle of claim 1, wherein the first electrode and the secondelectrode are equal in dimension.
 10. An artificial muscle comprising: ahousing comprising an electrode region and an expandable fluid region;and an electrode pair positioned in the electrode region of the housing,the electrode pair comprising a first electrode and a second electrode,the first electrode and the second electrode each comprise a pair of tabportions and a bridge portion interconnecting the pair of tab portions,the pair of tab portions extending parallel to one another to define agap portion between the pair of tab portions, the gap portion having aconstant gap width extending along a tab length of the pair of tabportions.
 11. The artificial muscle of claim 10, further comprising: afirst terminal extending from a tab portion of the first electrode; anda second terminal extending from a tab portion of the second electrode.12. The artificial muscle of claim 10, wherein the housing comprises afirst film layer and a second film layer partially sealed to one anotherto define a sealed portion of the housing, the housing further definingan unsealed portion surrounded by the sealed portion, wherein theelectrode region and the expandable fluid region of the housing aredisposed in the unsealed portion.
 13. The artificial muscle of claim 12,wherein the first film layer and the second film layer each comprise asubfilm layer, a backing layer, and a reinforcing layer provided betweenthe subfilm layer and the backing layer.
 14. The artificial muscle ofclaim 13, wherein the reinforcing layer has an elasticity greater thanan elasticity of the subfilm layer and the backing layer.
 15. A methodfor actuating an artificial muscle assembly, the method comprising:generating a voltage using a power supply electrically coupled to anelectrode pair of an artificial muscle, the artificial muscle comprisinga housing with an electrode region and an expandable fluid region,wherein: the electrode pair is positioned in the electrode region of thehousing; the electrode pair comprises a first electrode and a secondelectrode, the first electrode and the second electrode each comprise apair of tab portions and a bridge portion interconnecting the pair oftab portions, the pair of tab portions extending parallel to one anotherto define a gap portion between the pair of tab portions, the gapportion having a constant gap width extending along a tab length of thepair of tab portions; and a dielectric fluid is housed within thehousing; and applying the voltage to the electrode pair of theartificial muscle, thereby actuating the electrode pair from anon-actuated state and an actuated state such that the dielectric fluidis directed into the expandable fluid region of the housing and expandsthe expandable fluid region.
 16. The method of claim 15, furthercomprising: partially heat sealing a first film layer of the housing toa second film layer of the housing to define a sealed portion and anunsealed portion surrounded by the sealed portion, wherein the electroderegion and the expandable fluid region of the housing are disposed inthe unsealed portion.
 17. The method of claim 15, further comprising:communicatively coupling a controller to the electrode pair; andoperating the controller to direct a voltage from the power supplyacross the first electrode and the second electrode to actuate theartificial muscle from the non-actuated state to the actuated state. 18.The method of claim 15, wherein the pair of tab portions of each of thefirst electrode and the second electrode extend parallel to one anotherand define a gap portion having a constant gap width adjacent the bridgeportion of each of the first electrode and the second electrode.
 19. Themethod of claim 15, wherein the housing comprises a first reinforcinglayer and a second reinforcing layer positioned substantially within theexpandable fluid region, the first reinforcing layer at least partiallyoverlapping the bridge portion of the first electrode, and the secondreinforcing layer at least partially overlapping the bridge portion ofthe second electrode.
 20. The method of claim 15, wherein the firstelectrode and the second electrode are equal in dimension.